Real-World Technology Ltd

RWT and the History of TVRO

Back in the mid-1970s we talked of TVRO -- Television Receive-Only. In those days
satellite TV reception was the preserve of the international operators,
Intelsat
and Intersputnik,
and the American CATV companies, introduced to satellite by
the likes of Showtime and HBO,
anxious to deliver their premium programming in
real time and high quality to every cable operator across the USA.

Intelsat Standard A Earth stations used 26-metre or larger dishes; the Soviet Orbita
terminals had 12-metre rigs to receive the inclined-orbit Molniya satellites. The
US CATV head-ends needed at least a 6-metre antenna to give 3dB margin
above threshold on the Satcom and Westar C-Band programme feeds, with
the current 120K LNAs. All rather more than the average backyard could
accommodate.

But in true American pioneer tradition, things were stirring down in the garage.
Experimenters, enthusiasts, radio hams, were working on microwave front ends
and FM demods, and beginning to realise that the satellite TV signals were not
out of reach.

H Paul Shuch
had designed microstrip low-noise converters for the radio
amateur 2.3, 3.4 and 5.6 GHz bands, and it was a small step to adapt them
to cover the 4 GHz satellite downlink band. Bob Taggart had designed a
low-cost petallized antenna for S-Band community satellite reception. In
1977 H Taylor
Howard, in between his work for NASA's
JPL, built up a complete C-Band satellite TV receiver from standard microwave
parts, with a 70 MHz FM demodulator.

Meanwhile in England RWT's co-founder Stephen J Birkill
had taken time out in 1975 from his duties as a BBC transmitter engineer, to build
an experimental system for receiving in England the SITE
(
Satellite Instructional Television Experiment) TV transmissions beamed to
Indian villages, from the NASA
ATS-6 geostationary
satellite at 860 MHz. At about the same time
Arthur C Clarke, the
acknowledged father (or was it grandfather?) of geosynchronous communications,
had a standard SITE terminal installed at his home in Sri Lanka, courtesy of the Indian
government.

Over the next three years Birkill extended his system to 4 GHz, receiving TV
pictures from Intelsat, Raduga, Molniya and the new Russian Gorizont
satellites, and 11 GHz, where the Italian experimental satellite Sirio and the
European Space Agency's OTS, flying
test bed for the Eutelsat series, were
downlinking. All this work was done with home-built low-noise block
downconverters (LNBs) and an ex-BBC 2.4-metre dish.

In 1978 Bob Cooper, a cable TV technical journalist and amateur radio enthusiast
operating out of Oklahoma City, heard of Birkill's small dish work and invited
him (and his receiver) over to CCOS-78 in Oklahoma, ostensibly a cable
TV operators' conference and trade show but destined to become the
world's first home satellite TV gathering. Cooper brought Birkill together with
California's Taylor Howard and Rod Wheeler of Whitehorse, Yukon (later to
form Norsat), Jim Vines
(Paraframe), Bob Behar (Hero), Tom Humphries (SCI, M/A-COM), Royden
Freeland (ICM), Oliver Swan and other pioneers who helped begin the US
home TVRO revolution of 1979-82. At the 1978 show Birkill demonstrated
clean NTSC pictures from a 3-metre dish, and Wheeler, together with engineer
Steve Ritchie (Satco), presented the first prototype of a consumer TVRO receiver.
CCOS-78 also saw the first private satellite TV uplink, when, with TV facilities
provided by Dana Atchley III (ACE -- now D3 TV) and a borrowed "mobile"
10-metre 3-kilowatt 6 GHz uplink operated by the show's participants,
the conference proceedings were double-hopped to cable head-ends across
North America via US domestic satellites of the Satcom and Westar series.

On the way home from CCOS, Steve Birkill met up in Canada with
ex-BBC engineering colleague Maurice J Lovelock, and they agreed to form
Real-World Technology, to design tuners, feeds and LNAs and
provide technical consultancy services for the coming home-satellite boom.

The next 2 years saw an explosive growth in TVRO interest. Bob
Cooper was the driving force, writing numerous articles in the
popular electronics press and being interviewed for major magazines
including Playboy and Time, as well as appearing on national
television to demonstrate the potential of small-dish TVRO for
bringing high quality multichannel entertainment into rural homes
poorly served by terrestrial TV. "Small dish" still meant 3 metres
or more, as the US domestic satellites were limited to about
37dBW peak EIRP and commercial C-Band LNAs had only just begun
to achieve noise temperatures as low as 85K. But in rural and
suburban America a 10 or 12-foot dish in the backyard was no
great problem.

Cooper's 1979 Oklahoma show (SPTS-79) was the first dedicated totally
to satellite, to be followed by 3 shows in 1980: at Miami in January,
San Jose in July, and Houston in November. Many more innovators
were coming forward, with receivers -- Andy Hatfield (Avcom), Paul
Shuch, John Ramsey (Sat-Tec), Clyde Washburn (Earth Terminals),
Robert Coleman, David Barker, Norman
Gillaspie; with antennas -- Jamie Gowen (ADM), Bob Taggart
(Chaparral), Bob
Luly (inventor of the umbrella antenna now used in L-Band transportable
satellite telephones); with LNAs -- Dexcel; as well as suppliers of feeds,
mounts and accessories. Professional broadcast and CATV suppliers
also were seeing a new market, with Amplica, Avantek, Microwave
Associates, SCI, Anixter, Microdyne, Scientific Atlanta and others
taking an active interest.

RWT's Steve Birkill sent over a replica of his
original circularly-polarized 90-degree scalar horn feed, for tests with
US reception of the Russian Molniya and Gorizont satellites -- his
studies of the Soviet space program (with Geoff Perry) and monitoring
of their inclined-orbit operations meant he could instruct the
Americans where in their northern sky to point their dishes (the western
quasi-stationary point of the Molniya orbit, over Hudson Bay, Canada, was the one
used by the Russians for TV distribution). The
scalar horn concept, though not new, inspired others -- most
successfully Chaparral, to develop their own scalars for the home
market, replacing the rectangular pyramidal horns formerly used and
leading naturally to the rotating-probe designs. Complete TVRO
system prices fell below the $4000 mark; trade organisation SPACE
(since supplanted by SBCA)
and the first dealerships were established.

Birkill also began a series of articles for Bob Cooper's journal
CATJ, and later for the influential "Coop's Satellite Digest",
covering the technology of TVRO, with explanations of such
issues as block downconversion (most converters of the day
were tunable), feed horn design, LNA design (a practical
D-i-Y example used Plessey GaAsFETs), tracking polar mount geometry
(introducing the concept of declination offset), Ku-Band techniques
and threshold extension demodulators.
International satellite reception was also covered, as the USA's
fledgeling TVRO industry began to export its technology around
the world.

Five years into the American TVRO boom, with close on a million
10-foot dishes in use, the premium cable programmers began to realise
that these "home terminals" could be an additional source of revenue
beyond their normal CATV business. Channels like HBO began to
encrypt their transmissions with GI's
VideoCipher, and, although there
were still well over 100 TV channels in clear, the growth of TVRO
began seriously to slow down. By the time IRDs and subscriber
management systems were in place, some of the magic had gone.
TVRO had lost its pioneer charm and become another arm of Big
Business. And America began to think in terms of a future small-dish
DBS.

But in Europe things were just beginning. By 1982 Steve Birkill had
quit his BBC career -- at that time he was Transmitter Manager at
the Holme Moss / Emley Moor high power TV station complex in Northern
England -- to concentrate full time on RWT and the satellite business.

To be continued ...

Where are they now?

Bob Cooper, after a spell in the Caribbean, moved to New Zealand,
where he now runs SatFACTS monthly.